New Longevity Theory Released
That bottlenose dolphins and pilot whales baby-sit, guard and even breastfeed their grandchildren may seem to be the kind of Discovery-Channel factoid only worth mentioning around the water cooler at work, but it represents a key element in a widely praised new theory of aging published in the Proceeding of the National Academy of Sciences, Online Early Edition (July 14, 2003).
The new theory, proposed by Ronald D. Lee, Ph.D., of the University of California, Berkeley, suggests that natural selection favors animals capable of devoting energy and resources to insuring the survival of the next generation. Dryly titled "Rethinking the Evolutionary Theory of Aging: Transfers, Not Births, Shape . Senescence in Social Species," Lee's paper is the first to add intergenerational nurturing to the longevity equation.
NURTURING IMPORTANT FOR EVOLUTION
Lee, a demographer who has advised the Social Security Administration on longevity projections, explains that after birth, all mammals including primates, all birds, many insects and some fish contribute to their descendants "either through direct parental care or through grandparental care." He asserts that nurturing behavior is as important as fertility and reproduction for the evolution of a species' longevity and long-term survival.
In future research, Lee's paper recommends, "For empirical work, measures of transfers would ideally include not just food, but also such activities as warming, fanning, guarding, carrying, leading and teaching . …